The present invention relates to a carrying apparatus and an image forming apparatus which are comprised in, for example, an electrophotographic copying machine carrying paper sheets.
In some electrophotographic copying machines, images can be formed on both surfaces of a paper sheet. When images are formed on both surfaces of a paper sheet in these electrophotographic copying machines, paper sheets are fed from a sheet feed cassette through a sheet carrying route to an image forming section (hereinafter called simply an ADU). An image is formed on the front surface of the paper sheet thus fed to the image forming section and is then once stacked and contained into an intermediate tray. Subsequently, the paper sheet thus stacked and contained in the intermediate tray is fed again to the image forming apparatus, with its surfaces reversed. An image is then formed on its back surface. In this manner, images are formed on both surfaces of the paper sheet which is then discharged onto a sheet discharge tray.
Paper sheets stacked on the intermediate tray are applied with static electricity.
Meanwhile, electrostatic charges have been applied to paper sheets stacked on the intermediate tray, for example, through a transfer process at the image forming section. Therefore, paper sheets easily tend to be fed stuck to each other due to static electricity, when they are fed again from the intermediate tray.
In addition, since a paper sheet having a surface on which an image has been formed must once be stacked and contained in the intermediate tray, an image cannot be formed sequentially on its back surface. Time loss is hence caused so that the image forming efficiency is lowered.
To solve the above-described problems of paper sheets being fed stuck to each other and the image forming efficiency being lowered, development has been made in an electrophotographic copying machine which adopts a so-called non-stack ADU.
In this kind of electrophotographic copying machine, the intermediate tray is excluded from the ADU. Images are formed sequentially on the surfaces of a plurality of sheets. Thereafter, these paper sheets are directly sent to the image forming section, reversed by a reverse carrying means, and images are formed on the back surfaces of the paper sheets.
In some cases, the non-stack ADU is used with an accounting device such as a coin controller attached to the ADU. If a total of 4 pages are double-side-printed on two paper sheets in an electrophotographic copying machine attached with the accounting device, for example, there may be a case that the inserted money runs short at the time point when printing on pages 1, 2, and 4 pages is finished.
In this case, the paper sheet on which the third page should be printed is discharged without carrying out printing, or is kept on the ADU in the conventional apparatus.
It is, however, unkind to users to discharge the paper sheets without completing the printing process.
On the other hand, if a paper sheet is kept on the ADU, it may be curled if it is positioned in the corner section of the ADU.
Further, if a paper sheet is kept in a fixing device in an apparatus in which the sheet reverse mechanism serves also the fixing device, the paper sheet may be burnt, emit smoke, or catch fire.
Meanwhile, the non-stack ADU can be opened/closed in accordance with the operation of opening/closing an open/close door. If a paper sheet jams while carrying the paper sheet, the open/close door can be opened to remove the paper sheet. Therefore, if the door is opened with a paper sheet still kept on the ADU, there is a drawback that the paper sheet kept on the ADU falls to the ground and gets dirty.
The present invention has been made in view of the situation described above and has an object of providing a carrying apparatus and an image forming apparatus capable of keeping a transfer object (to which an image should be transferred), without curling or burning it or dropping it when an open/close door is opened.
A carrying apparatus according to the present invention comprises: a carrying device for carrying an object to be carried, along a carrying route having a straight part and an arc-like corner part; a straight escape part provided in the carrying device; and a control device for letting the object carried along the carrying route escape temporarily to the escape part and for keeping it therein, if necessary.
An image forming apparatus according to the present invention comprises: an image forming device for forming an image on an image carrier; a transfer device for transferring the image formed by the image forming device, to a transfer object to which the image should be transferred; a reverse carrying device for carrying the transfer object having one surface to which the image has been transferred, along a reverse carrying route having a straight part and an arc-like corner part, to reverse the transfer object, and for feeding the transfer object again to the transfer device to transfer an image to another surface thereof; a straight escape part provided in the reverse carrying device; and a control device for letting a carrying object to be carried, which is carried along the reverse carrying route, escape temporarily to the escape part, and for keeping the carrying object therein, if necessary.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.